Project description:We used phylogenetic low-density microarrays targeting the 16S rRNA gene to characterize the gingival flora of acute noma and acute necrotizing gingivitis lesions, and compared them to healthy control subjects of the same geographical and social background. Various types of samples were collected (column characteristics); patients from the same hospital without mouth infection (H), matched control populations (T), patients suffering gengivitis (Gengivitis), patient suffering NOMA (noma), patient suffering NOMA receiving antimicrobials (N-ATB). Sampled from patients were retrieved from both sides (column Description); healthy- or lesion-side of the mouth. All controls are matched with specific patients (see column patient category and number) We designed low-density 16S rDNA arrays representing 339 different phylotypes. We used an arbitrary cutoff of 1% of overall abundance to select from this dataset the most abundant sequences for probe design. Using this cutoff, the 132 most abundant 16S rRNA gene sequences were scanned for probes respecting defined physico-chemical properties (Tm = 65M-BM-15M-BM-0C; probe length = 23M-bM-^@M-^S50 nt; < -5.0 kcal/mol for hairpins; < -8.0 kcal/mol for self-dimers; and dinucleotide repeats shorter than 5 bp) using a commercial software (Array Designer TM 2.0 by Premier Biosoft). The 335 oligonucleotide probes were synthesized with a C6-linker with free primary amine (Sigma-Aldrich) and spotted on ArrayStrips microarrays (Clondiag GmbH, Jena, Germany).
Project description:The advent of culture independent approaches has greatly facilitated insights into the vast diversity of bacteria and the ecological importance they hold in nature and human health. Recently, metagenomic surveys and other culture-independent methods have begun to describe the distribution and diversity of microbial metabolism across environmental conditions, often using 16S rRNA gene as a marker to group bacteria into taxonomic units. However, the extent to which similarity at the conserved ribosomal 16S gene correlates with different measures of phylogeny, metabolic diversity, and ecologically relevant gene content remains contentious. Here, we examine the relationship between 16S identity, core genome divergence, and metabolic gene content across the ancient and ecologically important genus Streptomyces. We assessed and quantified the high variability of average nucleotide identity (ANI) and ortholog presence/absence within Streptomyces, even in strains identical by 16S. Furthermore, we identified key differences in shared ecologically important characters, such as antibiotic resistance, carbohydrate metabolism, biosynthetic gene clusters (BGCs), and other metabolic hallmarks, within 16S identities commonly treated as the same operational taxonomic units (OTUs). Differences between common phylogenetic measures and metabolite-gene annotations confirmed this incongruence. Our results highlight the metabolic diversity and variability within OTUs and add to the growing body of work suggesting 16S-based studies of Streptomyces fail to resolve important ecological and metabolic characteristics. See publication: https://doi.org/10.3389/fmicb.2019.02170.
The work (proposal:https://doi.org/10.46936/10.25585/60001100) conducted by the U.S. Department of Energy Joint Genome Institute (https://ror.org/04xm1d337), a DOE Office of Science User Facility, is supported by the Office of Science of the U.S. Department of Energy operated under Contract No. DE-AC02-05CH11231.
2023-11-02 | MSV000093247 | MassIVE
Project description:16S rDNA sequences of 97 samples
Project description:Prostate of SD rats was injected with 0.1 ml 1% carrageenan to induce chronic nonbacterial prostatitis, and the control rats injected with sterile saline. Then, the cecal contents were collected for 16S rDNA sequencing.
Project description:We characterized the bacterial diversity of chlorinated drinking water from three surface water treatment plants supplying the city of Paris, France. For this purpose, we used serial analysis of V6 ribosomal sequence tag (SARST-V6) to produce concatemers of PCR-amplified ribosomal sequence tags (RSTs) from the V6 hypervariable region of the 16S rRNA gene for sequence analysis. Using SARST-V6, we obtained bacterial profiles for each drinking water sample, demonstrating a strikingly high degree of biodiversity dominated by a large collection of low-abundance phylotypes. In all water samples, between 57.2-77.4% of the sequences obtained indicated bacteria belonging to the Proteobacteria phylum. Full-length 16S rDNA sequences were also generated for each sample, and comparison of the RSTs with these sequences confirmed the accurate assignment for several abundant bacterial phyla identified by SARST-V6 analysis, including members of unclassified bacteria, which account for 6.3-36.5% of all V6 sequences. These results suggest that these bacteria may correspond to a common group adapted to drinking water systems. The V6 primers used were subsequently evaluated with a computer algorithm to assess their hybridization efficiency. Potential errors associated with primer-template mismatches and their impacts on taxonomic group detection were investigated. The biodiversity present in all three drinking water samples suggests that the bacterial load of the drinking water leaving treatment plants may play an important role in determining the downstream community dynamics of water distribution networks. 3 different drinking water samples (Orly, Ivry, Joinville drinking water sample)
Project description:In S. cerevisiae, replication timing is controlled by epigenetic mechanisms restricting the accessibility of origins to limiting initiation factors. About 30% of these origins are located within repetitive DNA sequences such as the ribosomal DNA (rDNA) array, but their regulation is poorly understood. Here, we have investigated how histone deacetylases (HDACs) control the replication program in budding yeast. This analysis revealed that two HDACs, Rpd3 and Sir2, control replication timing in an opposite manner. Whereas Rpd3 delays initiation at late origins, Sir2 is required for the timely activation of early origins. Moreover, Sir2 represses initiation at rDNA origins whereas Rpd3 counteracts this effect. Remarkably, deletion of SIR2 restored normal replication in rpd3 cells by reactivating rDNA origins. Together, these data indicate that HDACs control the replication timing program in budding yeast by modulating the ability of repeated origins to compete with single-copy origins for limiting initiation factors. MNase-seq analysis of nucleosome position in wt, sir2 and rpd3 cells, aligned against genomic DNA (sacCer3; *sorted_s3.bed) and rDNA sequences (*rdna_nucleosomes.bed)